JPH06209071A - Resin sealed type semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To prevent the occurrence of delamination between an inter-chip resin and package resin which may result in package cracks. CONSTITUTION:A first semiconductor chip 3 and second semiconductor chip 4 having a larger size than the chip 3 are counterposed to each other and their electrodes pads 3a and 4a are connected to each other through solder bumps 7. Then the space between the chips 3 and 4 is filled up with a reinforcing inter-chip resin 2 by injecting the resin 2 into the space and the peripheral side face of the resin 2 is flushed with that of the chip 3 by removing the fillet section (fin-like section) squeezed out from the chip 3. After the second chip 4 is die-bonded to the chip mounting section 6b of a lead frame 6 and outside connecting terminals 4b on the chip 4 are connected to leads 6a through bonding wires 5, the whole body is molded with a package resin 1 except parts of the leads 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device of a multi-chip module in which a plurality of semiconductor chips are faced to each other and electrically coupled to each other, and then the whole is packaged with a resin, and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIG. 4 shows a sectional structure of a conventional semiconductor device of a multi-chip module of this type of plastic package.

The first semiconductor chip 3 and the second semiconductor chip 4 larger than the first semiconductor chip 3 are connected to the respective electrode pads 3
a and 4a are arranged face-to-face with the solder bumps 7 interposed therebetween, the solder bumps 7 are reflowed to electrically connect the two semiconductor chips 3 and 4, and then the dispenser is placed around the first semiconductor chip 3. The inter-chip resin 2 is injected and filled into the gap between the semiconductor chips 3 and 4 by using, for example, After the resin 2 between chips is cured, the back surface of the second semiconductor chip 4 is die-bonded to the chip mount portion 6b of the lead frame 6. Then, the external connection terminals 4b drawn out to the peripheral portion of the second semiconductor chip 4 and the leads 6a in the lead frame 6 are electrically connected via the bonding wires 5. Further, the entire lead 6a except for a part thereof is sealed by transfer molding of the package resin 1, and the portion of the lead 6a exposed to the outside of the package resin 1 is cut and bent, whereby a semiconductor device of a multi-chip module is formed. Has been completed.

It is necessary to inject and fill the inter-chip resin 2 in the gap between the two semiconductor chips 3 and 4 in advance and to cure the resin so that the solder bumps 7 are crushed by the pressure applied at the time of molding the package resin 1 or each semiconductor chip is crushed. This is to reinforce so that 3 and 4 will not be damaged.

[0005]

However, in the case of the semiconductor device of the multi-chip module having the above structure, in the reliability test after manufacturing, as shown in FIG. 5, at the interface between the inter-chip resin 2 and the package resin 1. It was found that peeling occurred and eventually caused defects such as package cracks 8 and the like.

This indicates that the adhesiveness between the package resin 1 and the inter-chip resin 2 is inferior to the adhesiveness between the package resin 1 and the semiconductor chips 3, 4 and the lead frame 6.

Since the inter-chip resin 2 is filled in the gap between the two semiconductor chips 3 and 4 so that the resin is soaked from the periphery of the first semiconductor chip 3, not only the interface between the two semiconductor chips 3 and 4 but also the The inter-chip resin 2 spreads thinly on the outer side of the semiconductor chip 3 of No. 1 to form the fillet portion (fin-shaped portion) 2a. As a result, the contact area between the inter-chip resin 2 and the package resin 1 becomes large. The interface between the inter-chip resin 2 and the package resin 1 has weak adhesion as described above, and if the contact area between the two is large due to the presence of the fillet portion 2a, the interface peeling is more likely to occur.

The above problem can be solved if a resin having good adhesiveness to the package resin 1 can be adopted as the resin 2 between chips, but the resin 2 between chips can withstand the temperature and pressure at the time of transfer molding and the solder bumps. It is necessary to be able to relieve the stress applied to No. 7, and it is extremely difficult to obtain a suitable alternative resin that simultaneously satisfies these two conditions. On the contrary, it is possible to change the package resin 1, but it is very difficult to change the type of resin that has been used for a long time in terms of moldability, which is also very difficult. is there.

The present invention was devised in view of such circumstances, and an object thereof is to prevent delamination between the resin between chips and the package resin, which causes a package crack.

[0010]

A resin-sealed semiconductor device according to the present invention comprises a first semiconductor chip and a second semiconductor chip larger than the first semiconductor chip.
Is electrically connected via a solder bump interposed between the two semiconductor chips in a state of being face-to-face, and a resin between the chips for reinforcement in the gap between the first and second semiconductor chips. Is a resin-encapsulated semiconductor device that is entirely filled and cured with a package resin, and a peripheral side surface of the inter-chip resin that is filled and cured in the gap between the two semiconductor chips is the first semiconductor chip. It is characterized in that it is formed substantially flush with the peripheral side surface of the.

The method of manufacturing a resin-encapsulated semiconductor device according to the present invention includes a first semiconductor chip and a second semiconductor chip larger than the first semiconductor chip.
And electrically connecting the semiconductor chip with the semiconductor chip with a solder bump interposed therebetween, and injecting and filling a resin between chips for reinforcement into the gap between the first and second semiconductor chips. And a step of curing the filled inter-chip resin, and removing the fillet portion of the inter-chip resin protruding outside the first semiconductor chip on the second semiconductor chip to remove the periphery of the inter-chip resin. The method is characterized by including the step of making the side surface flush with the peripheral side surface of the first semiconductor chip, and the step of molding the whole with a package resin.

[0012]

According to the resin-sealed semiconductor device of the present invention, the peripheral side surface of the inter-chip resin for reinforcement filled and cured between both semiconductor chips and the peripheral side surface of the first semiconductor chip are flush with each other. Since the contact area between the package resin and the resin between chips that is molded afterwards is minimized, interfacial peeling is less likely to occur even if the package resin and the resin between chips are poor in adhesion. .

Further, according to the method of manufacturing a resin-sealed semiconductor device of the present invention, even if the inter-chip resin for reinforcement protrudes outside the first semiconductor chip to form a fillet portion (fin-like portion), Since the fillet portion is removed so that the peripheral side surface of the inter-chip resin is flush with the peripheral side surface of the first semiconductor chip, the fluidity of the inter-chip resin is enhanced and the inter-chip resin can be easily filled between both semiconductor chips. However, the interface peeling between the package resin to be molded later and the inter-chip resin is less likely to occur.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a resin-sealed semiconductor device and a method of manufacturing the same according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing a structure of a semiconductor device of a multi-chip module in a completed state, and FIGS. 2 and 3 are sectional views showing a structure at an intermediate stage of a manufacturing process.

As shown in FIG. 2, first, the first semiconductor chip 3 and the larger second semiconductor chip 4 are electrically connected via the solder bumps 7. That is, the second
A solder layer is formed on the electrode pad 4a of the semiconductor chip 4, and the electrode pad 3 of the first semiconductor chip 3 is formed on the solder layer.
The first semiconductor chip 3 and the second semiconductor chip 4 are arranged face-to-face so that a contacts. Then, the solder layer is reflowed by applying heat to electrically connect the electrode pad 3 a and the electrode pad 4 a via the solder bump 7.

Then, the inter-chip resin 2 for reinforcement is injected and filled from around the first semiconductor chip 3 into the gap between the two semiconductor chips 3 and 4 using a dispenser or the like. It is necessary to inject and fill the inter-chip resin 2 into the gap between the two semiconductor chips 3 and 4 in advance and to cure the resin 2 so that the solder bumps 7 are crushed by the pressure applied at the time of molding the package resin 1, which will be described later, or each semiconductor This is to reinforce the chips 3 and 4 so as not to be damaged.

When the resin 2 between chips is injected and filled, the fluidity of the resin 2 between chips is increased by heating both semiconductor chips 3 and 4, thereby facilitating the filling of the gap between the semiconductor chips 3 and 4. ing.

However, due to the increase in the fluidity of the inter-chip resin 2 as described above, the inter-chip resin 2 is not only formed in the gap between the semiconductor chips 3 and 4, but also in the second semiconductor chip 4.
In the above, it spreads thinly over a wider area than the first semiconductor chip 3. After that, the inter-chip resin 2 is cured, but the shape when cured is a fillet portion (fin-shaped portion) that spreads outside the periphery of the first semiconductor chip 3 as shown in the figure.
2a has been formed.

If this fillet portion 2a is left as it is, when the package resin 1 described later is molded,
Since the contact area between the resin 2 between chips and the package resin 1 becomes large and the adhesion at the contact interface is relatively weak, the interface peeling easily occurs due to aging, which causes defects such as package cracks. It is easy to become.

Therefore, as shown in FIG. 3, the fillet portion 2a expanded to the outside of the first semiconductor chip 3 is cut,
It is removed by a mechanical method such as polishing or a physicochemical etching method, and processed so that the peripheral side surface of the interchip resin 2 is flush with the peripheral side surface of the first semiconductor chip 3. The solder bumps 7 are kept embedded in the resin 2 between chips.

Next, as shown in FIG. 1, the back surface of the second semiconductor chip 4 is die-bonded to the chip mount portion 6b of the lead frame 6. Then, the external connection terminal 4 b drawn out to the peripheral portion of the second semiconductor chip 4 and the connection portion of the lead 6 a in the lead frame 6 are electrically connected via the bonding wire 5. Further, the entire lead 6a except for a part is sealed by transfer molding of the package resin 1.

As the package resin 1, what has been used as a proven product has been used, and it is not necessary to particularly consider the adhesion with the resin 2 between chips. Further, it is not necessary to consider the adhesiveness with the package resin 1 as the inter-chip resin 2, and the stress applied to the solder bumps 7 can be alleviated by withstanding the temperature and pressure of the package resin 1 during transfer molding. Anything will do. This compensates for the cost required for removing the fillet portion 2a, and further reduces the cost.

Finally, after the package resin 1 is hardened, the portions of the leads 6a exposed to the outside of the package resin 1 are cut and bent to complete the semiconductor device of the multichip module.

In the resin-sealed semiconductor device manufactured as described above, the fillet portion 2a is removed, and the peripheral side surface of the inter-chip resin 2 is flush with the peripheral side surface of the first semiconductor chip 3. Since the contact area with the package resin 1 is significantly reduced, even if the adhesion between the chip resin 2 and the package resin 1 is not so good, the interface between the chip resin 2 and the package resin 1 is reduced. It is possible to suppress the occurrence of peeling in the semiconductor device, prevent defects such as package cracks, and improve the reliability of the semiconductor device.

In the above embodiment, the case where the first semiconductor chip 3 is one has been described for simplification of description, but the present invention is not limited to this, and the second semiconductor chip 4 is used. First semiconductor chip 3 connected to
May be 2 or more. Further, both semiconductor chips 3 and 4 do not necessarily have to have active elements, and either one may be a silicon substrate on which aluminum wiring is simply formed.

[0026]

According to the resin-encapsulated semiconductor device of the present invention, since the contact area between the resin between chips and the package resin is minimized, the interfacial peeling between them is less likely to occur, and the resin between chips and the package resin are less likely to occur. In other words, even if a material having particularly good adhesion is not used, in other words, it is possible to prevent the occurrence of defects such as package cracks and improve the reliability of the semiconductor device while suppressing the cost increase.

Further, according to the method of manufacturing a resin-sealed semiconductor device according to the present invention, the fluidity of the resin between chips is increased to facilitate the filling of the resin between chips between the two semiconductor chips, but at the same time, the molding is performed later. It is possible to prevent the occurrence of interface peeling between the package resin and the resin between the chips, and it is possible to manufacture a highly reliable resin-encapsulated semiconductor device with few defects such as package cracks.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a resin-sealed semiconductor device according to an embodiment of the present invention in a completed state.

FIG. 2 is a cross-sectional view showing a state in which a resin between chips is injected and filled in an example.

FIG. 3 is a cross-sectional view showing a state in which a fillet portion of resin between chips is removed in the example.

FIG. 4 is a sectional view showing a semiconductor device of a multi-chip module of a plastic package according to a conventional example.

FIG. 5 is a cross-sectional view showing a state in which a package crack has occurred in a conventional semiconductor device.

[Explanation of symbols]

 1 ... Package resin 2 ... Chip-to-chip resin 2a ... Fillet part (fin part) 3 ... First semiconductor chip 3a ... Electrode pad 4 ... Second semiconductor chip 4a ... Electrode pad 4b. External connection terminal 5 ... Bonding wire 6 ... Lead frame 6a ... Lead 6b ... Chip mount part 7 ... Solder bump 8 ... Package crack

Claims (2)

[Claims] 1. A first semiconductor chip and a second semiconductor chip, which is larger than the first semiconductor chip, are electrically connected to each other via solder bumps interposed therebetween in a state of being arranged facing each other. A resin-encapsulated semiconductor device in which the inter-chip resin for reinforcement is filled and cured in the gap between the second semiconductor chips, and the whole is molded with a package resin, and the gap between the semiconductor chips is filled and cured. A resin-encapsulated semiconductor device, wherein a peripheral side surface of the resin between chips thus formed is formed to be substantially flush with a peripheral side surface of the first semiconductor chip. 2. A step of electrically connecting a first semiconductor chip and a second semiconductor chip, which is larger than the first semiconductor chip, to each other with solder bumps interposed therebetween, and both the first and second semiconductor chips. A step of injecting and filling a resin between chips for reinforcement into a gap between the semiconductor chips, a step of curing the filled resin between chips, and a step of protruding to the outside of the first semiconductor chip on the second semiconductor chip. And removing the fillet portion of the resin between chips to make the peripheral side surface of the resin between chips flush with the peripheral side surface of the first semiconductor chip,
And a step of molding the entire body with a package resin.